How to set up audio streaming (internet radio) in Linux

This tutorial will show you how you can go live with your own internet radio station in a few minutes.

Demystifying “streams”

There is a lot of information, disinformation and irrelevant information about this in the internet. When you listen to internet radio, and you inspect the network requests in your Google Chrome Developer Tools (yes, you should use Chrome anyway), you will discover that a ‘magickal’ stream is nothing else than a blatantly simple HTTP download of a regular file which never finishes. Yup, jawdroppingly simple.

What do you need?

In order to broadcast audio (e.g. internet radio) into the internet, you need

a remotestreaming server with high bandwidth to which many clients can collect

a localstream generator, which is sending a single stream to the streaming server

The following tutorial shows how you can easily achieve this with free and open source tools which are part of the Debian (Ubuntu) distributions. It will take you 15 minutes to start your first rudimentary broadcast.

We will use Icecast2 as a streaming server, simply for the reason that it is part of the Debian distribution and that I got it to work immediately. As the local stream generator we will use darkice, for the same reasons.

Why not Windows? Well, since the majority of remote servers are running Linux distributions, you can use Icecast2 anyway. If you want to use a different stream generator for Windows, you can do so. This screencast shows you how it’s done.

Icecast2

Very much so. ICEcast is an industry standard platform used by thousands and thousands of radio stations all over the world. Its wide compatibility means people can listen with most players and operating systems.

Listeners will be able to connect to your MP3 stream from all over the world, with all the popular media players including Windows Media Player, iTunes, Winamp, Realplayer, XMMS, and many more media players besides.

Although incredibly simple, it can cope with even the heaviest demands and will not break under pressure. Its simplicity works to the broadcaster and listeners favor.

You would do the following steps on a server which is located at a large internet node with enough bandwidth to serve all your audience. To install, simply type

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apt-get install icecast2

During the installation you will be asked if you want to configure Icecast2. Answer yes. You will be asked the hostname. Here simply leave the default “localhost”. Next, you will be asked for source, relay and administration passwords. For testing, leave “hackme”. If you want to change the configuration at a later point, edit the configuration file
/etc/icecast2/icecast.xml

Next, you have to enable the Icecast2 server by setting
ENABLE in the configuration file
/etc/default/icecast2 to
true .

Now, start the server by typing

service icecast2 start

You now can access the web admin interface on port 8000 of your machine:

Icecast2 web-based admin interface

The log file is in
/var/log/icecast2/error.log and
access.log . Best to
tail -f both files to observe what is going on.

Darkice

Darkice is a stream generator. It encodes audio into various formats (e.g. ogg, mp3, etc.) from various inputs (e.g. microphone jack, line-in jack, or the stereo mix of your operating system) and sends a single stream to our Icecast2 server, which in turns re-broadcasts it to all connected clients.

To install, simply type:

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apt-get install darkice

By default it does not install a configuration file. But there is an example one in the documentation. Copy this to the /etc directory:

cp /usr/share/doc/darkice/examples/darkice.cfg /etc

You will need to edit this file according to your needs. Here is an example that worked for me:

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# this section describes general aspects of the live streaming session

[general]

duration = 0

bufferSecs = 5

reconnect = yes

[input]

device = default

sampleRate = 44100

bitsPerSample = 16

channel = 2

[icecast2-0]

bitrateMode = abr

format = vorbis

bitrate = 96

server = 192.168.0.250

port = 8000

password = hackme

mountPoint = example1.ogg

name = DarkIce trial

description = This is only a trial

url = http://www.yourserver.com

genre = my own

public = yes

localDumpFile = dump.ogg

Make sure that the password and the IP address of the Icecast2 server (which we installed earlier on the other machine) match. Also, remember the mountPoint of this stream. This is simply a label, in my case it is “example1”. Then you simply run as normal user

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darkice

It is a console-only application and you will see some messages. This is what I get:

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DarkIce 1.0 live audio streamer, http://code.google.com/p/darkice/

Copyright (c) 2000-2007, Tyrell Hungary, http://tyrell.hu/

Copyright (c) 2008-2010, Akos Maroy and Rafael Diniz

This is free software, and you are welcome to redistribute it

under the terms of The GNU General Public License version 3 or

any later version.

Using config file: /etc/darkice.cfg

Using ALSA DSP input device: default

Could not set POSIX real-time scheduling, this may cause recording skips.

Try to run darkice as the super-user.

The note about the realtime stuff is just a warning, it works for me nevertheless. It would be easy to run it as superuser.

Making a simple stream player

We will simply make a small website with one <audio> element. That is enough to play streams. Create an empty file called
streamtest.html with the following contents:

XHTML

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<html>

<body>

<audio controls>

<source src="http://192.168.0.250:8000/example1" />

</audio>

</body>

</html>

Make sure that the IP address corresponds to the server where the Icecast2 server is running on. Open this html file in a browser and click the play button. Now you should hear the same audio that the darkice client has as its input.

Changing the audio input for darkice

In case you don’t have the Pulse Audio Volume control installed, install it with

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apt-get install pavucontrol

Then run it. As soon as you have darkice running, the “Recording” tab will show the text “ALSA plug-in [darkice]: ALSA Capture from …” From the drop down you can select the input source. The text is a bit misleading. In my case “Monitor” means the stereo-mix of the entire computer (e.g. all system sounds, all played back audios). “Built-in Analog Stereo” means the microphone / line-in jack.

Pulse Audio volume control pavucontrol

For professional radio applications you of course would not use such a simple software mixer, but have an external hardware-based mixer to which all the microphones and the line-out of your computer are attached. Then you would connect the final output of the hardware mixer to your computer line-in and select “Built-in Analog Stereo” for darkice’s input.

Linux has a more professional audio system called Jack as a replacement for the standard system Pulse Audio (we were using Pulse Audio in the above tutorial, which is similar to what Windows uses). Both are running on the Linux Kernel’s sound system called ALSA.

Conclusion

In the face of tons of documentation and blogs in the internet it is surpirisingly easy to set up your own, simple internet radio station with zero investment, all thanks to the Open Source movement.

11 Responses to How to set up audio streaming (internet radio) in Linux

Michael
Do you think there is a way to make a “local” network radio station streaming real-time audio? I have linux computers in every room supplying music to my house, but I want to be able to broadcast the microphone output from a baby monitor linux box to the rest of the house.
Would you be able to suggest some keywords to google, maybe? The darkice/icecast solution has way too much latency, as does any ffmpeg solution i have come up with.

Thank you so much for this! I have been testing a way to stream the audio of local speaking events in my hometown. I will be running Icecast from a laptop at home and using a smartphone or another laptop to run darkice or similar client from a remote location. In order for me to get this to work, I had to use the public ip of the icecast machine in darkice and in the html code that I post on my blog. In the icecast xml i used the local ip. I also had to set up port forwarding in my router as well. It works great, although I sometimes need to restart the icecast service before initial connection but one i’m connected it’s stays that way.